Change minor child's last name, father died, and grandparents have visitation rights only.

I want to know what I need to do in order to change my seven year old daughter's last name to my married surname. Her biological father died when she was two; yet his mother and step-father have court ordered visitation with her. They do not have any other rights. I am the only managing conservator. My husband, my son, and I all have the same last name so I want my daughter to have ours also.